This core laboratory will provide gross and microscopic pathology support for projects using model systems for the delivery of various vectors. Samples are expected to be received from mice, rats, cotton rats, baboons, sheep, xenografts, and ultimately CF patients. The core director is Dr. Claire Langston, an experienced pediatric pulmonary pathologist. Expertise in in situ hybridization will be provided by Dr. Avi Orr-Urtreger who has published extensively with this method. This core facility will be located in the Research Histology Laboratory at Texas Children's Hospital. Procedures to be performed will include tissue handling and preparation, gross and microscopic pathological analysis, and evaluation of expression of transfected genes. Routine pathological stains will be used and a semiquantitative scoring system for pathology in the respiratory tract will be utilized. Histochemical detection of beta-galactosidase and immunohistochemical detection of adenoviral proteins and beta- galactosidase will be performed. Immunohistochemical detection of human CFTR will be performed using a variety of antibodies and detection methods. In situ hybridization for detection of transfected genes will be performed using human cDNA probes for transfection into rodents and using probes for the 3' untranslated region of transcripts in the case of samples from baboon or human tissue.